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Sep 22, 2013
09/13

by
Elizabeth H. Simmons

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Recent work by Burdman, Lane, and Rador has shown that B-meson mixing places stringent lower bounds on the masses of topgluons and Z' bosons in classic topcolor-assisted technicolor (TC2) models. This paper finds analogous limits on the Z' bosons of flavor-universal TC2 and non-commuting extended technicolor models, and compares the limits with those from precision electroweak measurements. A discussion of the flavor structure of these models (contrasted with that of classic TC2) shows that...

Source: http://arxiv.org/abs/hep-ph/0111032v4

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Sep 22, 2013
09/13

by
Elizabeth H. Simmons

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The Run I experiments at the Fermilab Tevatron Collider discovered the top quark and provided first measurements of many of its properties. Run II (and eventually the LHC and NLC experiments) promise to extend our knowledge of the top quark significantly. Understanding the top quark's large mass, and indeed the origin of all mass, appears to require physics beyond the Standard Model. Thus, the top quark may have unusual properties accessible to upcoming experiments.

Source: http://arxiv.org/abs/hep-ph/0011244v3

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Sep 23, 2013
09/13

by
Elizabeth H. Simmons

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The top quark is by far the heaviest known fermion [1]. In consequence, experiment is just beginning to explore its properties, and some of them may yet prove to be distinctly non-standard. The very size of the top quark's mass even hints at the possibility of a special role for top in electroweak symmetry breaking. This talk examines the top quark in the context of physics beyond the standard model, and discusses how Run II can help elucidate the true nature of top.

Source: http://arxiv.org/abs/hep-ph/9908511v1

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Sep 22, 2013
09/13

by
Elizabeth H. Simmons

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The origin of mass must lie in physics beyond the Standard Model. Dynamical electroweak symmetry breaking models like technicolor can generate masses for the W and Z bosons. Providing the large top quark mass and large top-bottom mass splitting while keeping rho parameter and flavor-changing neutral currents small requires new strong dynamics for the top and bottom quarks. In consequence, new particles are predicted at scales up to 10 TeV with signatures in jets or heavy flavors. Searches for...

Source: http://arxiv.org/abs/hep-ph/0004238v1

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Sep 18, 2013
09/13

by
Elizabeth H. Simmons

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This talk describes how modern theories of dynamical electroweak symmetry breaking have evolved from the original minimal QCD-like technicolor model in response to three key challenges: R_b, flavor-changing neutral currents, and weak isospin violation.

Source: http://arxiv.org/abs/hep-ph/0110196v3

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Sep 19, 2013
09/13

by
Nuria Rius; Elizabeth H. Simmons

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We consider experimental signatures of the standard model's minimal supersymmetric extension with a continuous $U(1)_R$ symmetry (MR model). We focus on the ability of existing and planned electron-positron colliders to probe this model and to distinguish it from both the standard model and the standard model's minimal supersymmetric extension with a discrete $R$-parity.

Source: http://arxiv.org/abs/hep-ph/9303302v2

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Jul 20, 2013
07/13

by
Vagish Hemmige; Elizabeth H. Simmons

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Technicolor with scalars is the simplest dynamical symmetry breaking model and one in which the predicted values of many observables may be readily calculated. This letter applies current LEP, Tevatron, CESR, and SLAC data from searches for neutral and charged scalars and from studies of b-quark physics to obtain bounds on technicolor with scalars. Expectations for how upcoming measurements will further probe the theory's parameter space are also discussed.

Source: http://arxiv.org/abs/hep-ph/0107117v1

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Sep 22, 2013
09/13

by
Elizabeth H. Simmons; Yumian Su

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We compute the one-loop corrections to the $Z \to b\bar{b}$ vertex in the $U(1)_R$ symmetric minimal supersymmetric extension of the standard model. We find that the predicted value of $R_b$ is consistent with experiment if the mass of the lighter top squark is no more than 180 GeV. Furthermore, other data combines to place a lower bound of 88 GeV on the mass of the light top squark. A top squark in this mass range should be accessible to searches by experiments at FNAL and LEP.

Source: http://arxiv.org/abs/hep-ph/9602267v4

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Sep 18, 2013
09/13

by
Iain Bertram; Elizabeth H. Simmons

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Using recent D0 data on the dijet mass spectrum, we present a limit on flavor-universal colorons. At 95% CL we find Mc/cot(theta) > 837 GeV. We discuss the implications of this limit for models of quark compositeness, non-standard gluon interactions, and dynamical electroweak symmetry breaking. In addition, we place a lower bound Lambda_A8 > 2.1 TeV on the scale of color-octet axial-vector contact interactions among quarks which could arise in models of quark compositeness.

Source: http://arxiv.org/abs/hep-ph/9809472v1

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Sep 21, 2013
09/13

by
R. Sekhar Chivukula; Elizabeth H. Simmons

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Technicolor and other theories of dynamical electroweak symmetry breaking invoke chiral symmetry breaking triggered by strong gauge-dynamics, analogous to that found in QCD, to explain the observed W, Z, and fermion masses. In this talk we describe why a realistic theory of dynamical electroweak symmetry breaking must, relative to QCD, produce an enhanced fermion condensate. We quantify the degree to which the technicolor condensate must be enhanced in order to yield the observed quark masses,...

Source: http://arxiv.org/abs/1011.2535v2

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Sep 22, 2013
09/13

by
Marko B. Popovic; Elizabeth H. Simmons

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We employ data from precision electroweak tests and collider searches to derive constraints on the possibility that weak-singlet fermions mix with the ordinary Standard Model fermions. Our findings are presented within the context of a theory with weak-singlet partners for all ordinary fermions and theories in which only third-generation fermions mix with weak singlets. In addition, we indicate how certain results can be applied more widely in theories containing exotic fermions.

Source: http://arxiv.org/abs/hep-ph/0001302v2

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Sep 19, 2013
09/13

by
Thorsten Ohl; Giulia Ricciardi; Elizabeth H. Simmons

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We perform a quantitative analysis of $D\bar{D}$ mixing in Heavy Quark Effective Field Theory (HqEFT) including leading order QCD corrections. We find an enhancement of the short-distance contribution by a factor of two or three.

Source: http://arxiv.org/abs/hep-ph/9301212v1

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Sep 22, 2013
09/13

by
Bogdan A. Dobrescu; Elizabeth H. Simmons

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We present a model of dynamical electroweak symmetry breaking in which the splitting between the top and bottom quark masses arises naturally. The W and Z masses are produced by a minimal technicolor sector, the top quark mass is given by the exchange of a weak-doublet technicolored scalar, and the other quark and lepton masses are induced by the exchange of a weak-doublet technicolor-singlet scalar. We show that, in the presence of the latter scalar, the vacuum alignment is correct even in the...

Source: http://arxiv.org/abs/hep-ph/9807469v1

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Jul 19, 2013
07/13

by
R. Sekhar Chivukula; Elizabeth H. Simmons

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Since the pioneering work of Eichten and Lane it has been known that the scale of the interactions responsible for the generation of the strange-quark mass in extended technicolor theories must, absent any "GIM-like" mechanism for suppressing flavor-changing neutral currents, be greater than of order 1000 TeV. In this note we point out that the constraint from the neutral D-meson system is now equally strong, implying that the charm quark mass must also arise from flavor dynamics at a...

Source: http://arxiv.org/abs/1005.5727v3

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Sep 18, 2013
09/13

by
Kevin R. Lynch; Elizabeth H. Simmons

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LEPI and LEPII data can be used to constrain technicolor models with light, neutral pseudo-Nambu-Goldstone bosons, Pa. We use published limits on branching ratios and cross sections for final states with photons, large missing energy, jet pairs, and b bbar pairs to constrain the anomalous Pa Z0 Z0, Pa Z0 photon, and Pa photon photon couplings. From these results, we derive bounds on the size of the technicolor gauge group and the number of technifermion doublets in models such as Low-scale...

Source: http://arxiv.org/abs/hep-ph/0012256v2

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Sep 21, 2013
09/13

by
R. Sekhar Chivukula; Elizabeth H. Simmons

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Motivated by models of holographic technicolor, we discuss a four-site deconstructed Higgsless model with nontrivial wavefunction mixing. We compute the spectrum of the model, the electroweak triple gauge boson vertices, and, for brane-localized fermions, the electroweak parameters to O(M^2_W/M^2_rho). We discuss the conditions under which "S" vanishes (even for brane-localized fermions) and the (distinct but overlapping) conditions under which the phenomenologically interesting decay...

Source: http://arxiv.org/abs/0808.2071v4

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Sep 21, 2013
09/13

by
Christopher T. Hill; Elizabeth H. Simmons

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The breaking of the electroweak symmetry, and origin of the associated ``weak scale,'' may be due to a new strong interaction. Theoretical developments over the past decade have led to viable models and mechanisms that are consistent with current experimental data. Many of these schemes feature a privileged role for the top quark, and third generation, and are natural in the context of theories of extra space dimensions at the weak scale. We review various models and their phenomenological...

Source: http://arxiv.org/abs/hep-ph/0203079v3

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Sep 23, 2013
09/13

by
Marko B. Popovic; Elizabeth H. Simmons

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Ordinary technicolor and extended technicolor cannot produce the heavy top quark unaided. We demonstrate that a flavor-universal extension of the color interactions combined with an extended hypercharge sector that singles out the third generation can provide the necessary assistance. We discuss current experimental constraints and suggest how collider experiments can search for the predicted new heavy gauge bosons.

Source: http://arxiv.org/abs/hep-ph/9806287v3

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Jun 27, 2018
06/18

by
R. Sekhar Chivukula; Arsham Farzinnia; Elizabeth H. Simmons

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The renormalizable coloron model is built around a minimally extended color gauge group, which is spontaneously broken to QCD. The formalism introduces massive color-octet vector bosons (colorons), as well as several new scalars and fermions associated with the symmetry breaking sector. In this paper, we examine vacuum stability and triviality conditions within the context of the renormalizable coloron model up to a cutoff energy scale of 100~TeV, by computing the beta-functions of all relevant...

Topics: High Energy Physics - Experiment, High Energy Physics - Phenomenology

Source: http://arxiv.org/abs/1504.03012

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Sep 22, 2013
09/13

by
Christopher D. Carone; Elizabeth H. Simmons; Yumian Su

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We consider the radiative decay $b\rightarrow s \gamma$, and the correction to the $Zb\overline{b}$ vertex in technicolor models with scalars. In these models, the scalar develops a vacuum expectation value when the technifermions condense, and the ordinary fermions develop masses via Yukawa couplings. Since the symmetry breaking sector involves both a fundamental scalar doublet and an isotriplet of composite scalars (the technipions), the phenomenology associated with the charged scalars is...

Source: http://arxiv.org/abs/hep-ph/9410242v2

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Jun 28, 2018
06/18

by
Elizabeth H. Simmons; R. Sekhar Chivukula; Pawin Ittisamai; Natascia Vignaroli

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Color-singlet and color-octet vector bosons predicted in theories beyond the Standard Model have the potential to be discovered as dijet resonances at the LHC. A color-singlet resonance that has leptophobic couplings needs further investigation to be distinguished from a color-octet one. In previous work, we introduced a method for discriminating between the two kinds of resonances when their couplings are flavor-universal, using measurements of the dijet resonance mass, total decay width and...

Topics: High Energy Physics - Phenomenology, High Energy Physics - Experiment

Source: http://arxiv.org/abs/1507.05868

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Sep 23, 2013
09/13

by
R. Sekhar Chivukula; Arsham Farzinnia; Roshan Foadi; Elizabeth H. Simmons

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We report the first complete calculation of QCD corrections to the production of a massive color-octet vector boson. Our next-to-leading-order (NLO) calculation includes both virtual corrections as well as corrections arising from the emission of gluons and light quarks, and we demonstrate the reduction in factorization-scale dependence relative to the leading-order approximation used in previous hadron collider studies. We show that the QCD NLO corrections to coloron production are as large as...

Source: http://arxiv.org/abs/1111.7261v3

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0.0

Jun 30, 2018
06/18

by
R. Sekhar Chivukula; Pawin Ittisamai; Elizabeth H. Simmons

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Electrically-neutral massive color-singlet and color-octet vector bosons, which are often predicted in Beyond the Standard Model theories, have the potential to be discovered as dijet resonances at the LHC. A color-singlet resonance that has leptophobic couplings needs further investigation to be distinguished from a color-octet one. In previous work, we introduced a method for discriminating between the two kinds of resonances when their couplings are flavor-universal, using measurements of...

Topics: High Energy Physics - Phenomenology, High Energy Physics - Experiment

Source: http://arxiv.org/abs/1406.2003

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0.0

Jun 30, 2018
06/18

by
R. Sekhar Chivukula; Elizabeth H. Simmons; Natascia Vignaroli

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Anticipating that a di-jet resonance could be discovered at the 14 TeV LHC, we present two different strategies to reveal the nature of such a particle; in particular to discern whether it is a quark-antiquark (qqbar), quark-gluon (qg), or gluon-gluon (gg) resonance. The first method relies on the color discriminant variable, which can be calculated at the LHC from the measurements of the di-jet signal cross section, the resonance mass and the resonance width. Including estimated statistical...

Topics: High Energy Physics - Phenomenology, High Energy Physics - Experiment

Source: http://arxiv.org/abs/1412.3094

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Sep 23, 2013
09/13

by
Tomohiro Abe; R. Sekhar Chivukula; Elizabeth H. Simmons; Masaharu Tanabashi

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We study the flavor structure of the three-site Higgsless model and evaluate the constraints on the model arising from flavor physics. We find that current data constrain the model to exhibit only minimal flavor violation at tree level. Moreover, at the one-loop level, by studying the leading chiral logarithmic corrections to chirality-preserving Delta F = 1 and Delta F = 2 processes from new physics in the model, we show that the combination of minimal flavor violation and ideal delocalization...

Source: http://arxiv.org/abs/1109.5856v1

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Jun 29, 2018
06/18

by
R. Sekhar Chivukula; Arsham Farzinnia; Kirtimaan Mohan; Elizabeth H. Simmons

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The renormalizable coloron model, which has previously been shown in the literature to be consistent with a wide array of theoretical and precision electroweak constraints, includes a pair of spinless bosons (one scalar, one pseudoscalar). We show that either of them, or both together if they are degenerate, could be responsible for the diphoton resonance signal for which both CMS and ATLAS have seen evidence. Because either of these bosons would be produced and decay through loops of spectator...

Topics: High Energy Physics - Phenomenology, High Energy Physics - Experiment

Source: http://arxiv.org/abs/1604.02157

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Jul 20, 2013
07/13

by
R. Sekhar Chivukula; Elizabeth H. Simmons; C. -P. Yuan

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We study an SU(3)^2 axigluon model introduced by Frampton, Shu, and Wang to explain the recent Fermilab Tevatron observation of a significant positive enhancement in the top quark forward-backward asymmetry relative to standard model predictions. First, we demonstrate that data on neutral B_d-meson mixing excludes the region of model parameter space where the top asymmetry is predicted to be the largest. Keeping the gauge couplings below the critical value that would lead to fermion...

Source: http://arxiv.org/abs/1007.0260v3

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Jun 28, 2018
06/18

by
Pawin Ittisamai; R. Sekhar Chivukula; Kirtimaan Mohan; Elizabeth H. Simmons

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A narrow resonance decaying to dijets could be discovered at the 14 TeV run of the LHC. To quickly identify its color structure in a model-independent manner, we introduced a method based on a color discriminant variable, determined from the measurements of the resonance's production cross section, mass and width. This talk introduces a more transparent theoretical formulation of the color discriminant variable that highlights its relationship to the branching ratios of the resonance into...

Topic: High Energy Physics - Phenomenology

Source: http://arxiv.org/abs/1510.08753

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Jul 19, 2013
07/13

by
R. Sekhar Chivukula; Mitchell Golden; Elizabeth H. Simmons

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We consider the constraints that critical dynamics places on models with a top quark condensate or strong extended technicolor (ETC). These models require that chiral-symmetry-breaking dynamics at a high energy scale plays a significant role in electroweak symmetry breaking. In order for there to be a large hierarchy between the scale of the high energy dynamics and the weak scale, the high energy theory must have a second order chiral phase transition. If the transition is second order, then...

Source: http://arxiv.org/abs/hep-ph/9210276v2

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Sep 22, 2013
09/13

by
R. Sekhar Chivukula; Elizabeth H. Simmons; Natascia Vignaroli

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In this paper we introduce a simple renormalizable model of an extended color gauge sector in which the third-generation quarks couple differently than the lighter quarks. In addition to a set of heavy color-octet vector bosons (colorons), the model also contains a set of heavy weak vector quarks. Mixing between the third-generation of quarks and the first two is naturally small, and occurs only through the (suppressed) mixing of all three generations with the heavy vector quarks. We discuss...

Source: http://arxiv.org/abs/1302.1069v4

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Sep 17, 2013
09/13

by
Kevin R. Lynch; Meenakshi Narain; Elizabeth H. Simmons; Stephen Mrenna

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Z' bosons that couple preferentially to the third generation fermions can arise in models with extended weak (SU(2)xSU(2)) or hypercharge (U(1)xU(1)) gauge groups. We show that existing limits on quark-lepton compositeness set by the LEP and Tevatron experiments translate into lower bounds of order a few hundred GeV on the masses of these Z' bosons. Resonances of this mass can be directly produced at the Tevatron. Accordingly, we explore in detail the limits that can be set at Run II using the...

Source: http://arxiv.org/abs/hep-ph/0007286v5

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Sep 23, 2013
09/13

by
R. Sekhar Chivukula; Arsham Farzinnia; Roshan Foadi; Elizabeth H. Simmons

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In this paper we discuss the global symmetries and the renormalizibility of Lee-Wick scalar QED. In particular, in the "auxiliary-field" formalism we identify softly broken SO(1,1) global symmetries of the theory. We introduce SO(1,1) invariant gauge-fixing conditions that allow us to show in the two-field formalism directly that the number of superficially divergent amplitudes in a LW Abelian gauge theory is finite. To illustrate the renormalizability of the theory, we explicitly...

Source: http://arxiv.org/abs/1006.2800v2

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Jun 29, 2018
06/18

by
R. Sekhar Chivukula; Roshan Foadi; Dennis Foren; Elizabeth H. Simmons

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We assess current experimental constraints on the bi-doublet + singlet model of top compositeness previously proposed in the literature. This model extends the standard model's spectrum by adding a custodially-embedded vector-like electroweak bi-doublet of quarks and a vector-like electroweak singlet quark. While either of those states alone would produce a model in tension with constraints from precision electroweak data, in combination they can produce a viable model. We show that current...

Topic: High Energy Physics - Phenomenology

Source: http://arxiv.org/abs/1605.06088

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Sep 22, 2013
09/13

by
R. Sekhar Chivukula; Rogerio Rosenfeld; Elizabeth H. Simmons; John Terning

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We discuss the phenomenology of models of dynamical electroweak symmetry breaking which attempt to generate the observed fermion mass spectrum. After briefly describing the variety of and constraints on proposed models, we concentrate on the signatures of colored pseudo-Nambu-Goldstone bosons and resonances at existing and proposed colliders. These particles provide a possibly unique signature: strongly produced resonances associated with electroweak symmetry breaking. (This is the subgroup...

Source: http://arxiv.org/abs/hep-ph/9503202v1

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Sep 20, 2013
09/13

by
R. Sekhar Chivukula; Arsham Farzinnia; Roshan Foadi; Elizabeth H. Simmons

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We analyze the tension between naturalness and isospin violation in the Lee-Wick Standard Model (LW SM), by computing tree-level and fermionic one-loop contributions to the post-LEP electroweak parameters and the Zbb coupling. The model is most natural when the LW partners of the gauge bosons and fermions are light, but small partner masses can lead to large isospin violation. The post-LEP parameters yield a simple picture in the LW SM: the gauge sector contributes to Y and W only, with leading...

Source: http://arxiv.org/abs/1002.0343v1

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Sep 23, 2013
09/13

by
R. Sekhar Chivukula; Pawin Ittisamai; Jing Ren; Elizabeth H. Simmons

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LHC searches for the standard model Higgs Boson in \gamma\gamma\ or \tau\tau\ decay modes place strong constraints on the light technipion state predicted in technicolor models that include colored technifermions. Compared with the standard Higgs Boson, the technipions have an enhanced production rate (largely because the technipion decay constant is smaller than the weak scale) and also enhanced branching ratios into di-photon and di-tau final states (largely due to the suppression of WW...

Source: http://arxiv.org/abs/1202.1505v1

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Sep 23, 2013
09/13

by
R. Sekhar Chivukula; Aaron Grant; Elizabeth H. Simmons

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It has recently been suggested that gauge invariance forbids the coupling of a massive color-octet vector meson to two gluons. While this is true for operators in an effective Lagrangian of dimension four or less, we demonstrate that dimension six interactions will lead to such couplings. In the case of technicolor, the result is a technirho-gluon-gluon coupling comparable to the naive vector meson dominance estimate, but with a substantial uncertainty. This has implications for several recent...

Source: http://arxiv.org/abs/hep-ph/0109029v3

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Sep 20, 2013
09/13

by
Shinya Matsuzaki; R. Sekhar Chivukula; Elizabeth H. Simmons; Masaharu Tanabashi

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In this paper we compute the the one-loop chiral logarithmic corrections to the S and T parameters in a highly deconstructed Higgsless model with only three sites. In addition to the electroweak gauge bosons, this model contains a single extra triplet of vector states (which we denote \rho^{\pm} and \rho^0), rather than an infinite tower of "KK" modes. We compute the corrections to S and T in 'tHooft-Feynman gauge, including the ghost, unphysical Goldstone-boson, and appropriate...

Source: http://arxiv.org/abs/hep-ph/0607191v7

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Jun 29, 2018
06/18

by
R. Sekhar Chivukula; Pawin Ittisamai; Kirtimaan Mohan; Elizabeth H. Simmons

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In the earliest stages of evaluating new collider data, especially if a small excess may be present, it would be useful to have a method for comparing the data with entire classes of models, to get an immediate sense of which classes could conceivably be relevant. In this paper, we propose a method that applies when the new physics invoked to explain the excess corresponds to the production and decay of a single, relatively narrow, $s$-channel resonance. A simplifed model of the resonance...

Topics: High Energy Physics - Phenomenology, High Energy Physics - Experiment

Source: http://arxiv.org/abs/1607.05525

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Jun 28, 2018
06/18

by
R. Sekhar Chivukula; Pawin Ittisamai; Kirtimaan Mohan; Elizabeth H. Simmons

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The LHC is actively searching for narrow dijet resonances corresponding to physics beyond the Standard Model. Among the many resonances that have been postulated (e.g., colored vectors, scalars, and fermions) one that would have a particularly large production rate at the LHC would be a scalar diquark produced in the s-channel via fusion of two valence quarks. In previous work, we introduced a color discriminant variable that distinguishes among various dijet resonances, drawing on measurements...

Topic: High Energy Physics - Phenomenology

Source: http://arxiv.org/abs/1507.06676

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Sep 21, 2013
09/13

by
R. Sekhar Chivukula; Neil D. Christensen; Elizabeth H. Simmons

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We discuss the properties of a model incorporating both a scalar electroweak Higgs doublet and an electroweak Higgs triplet. We construct the low-energy effective theory for the light Higgs-doublet in the limit of small (but nonzero) deviations in the rho parameter from one, a limit in which the triplet states become heavy. For small deviations in the rho parameter from one, perturbative unitarity of WW scattering breaks down at a scale inversely proportional to the renormalized vacuum...

Source: http://arxiv.org/abs/0712.0546v3

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Sep 20, 2013
09/13

by
R. Sekhar Chivukula; Nick Evans; Elizabeth H. Simmons

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Recently a new class of composite Higgs models have been developed which give rise to naturally light Higgs bosons without supersymmetry. Based on the chiral symmetries of ``theory space,'' involving replicated gauge groups and appropriate gauge symmetry breaking patterns, these models allow the scale of the underlying strong dynamics giving rise to the composite particles to be as large as of order 10 TeV, without any fine tuning to prevent large corrections to Higgs boson mass(es) of order...

Source: http://arxiv.org/abs/hep-ph/0204193v3

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Sep 23, 2013
09/13

by
R. Sekhar Chivukula; Arsham Farzinnia; Jing Ren; Elizabeth H. Simmons

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This paper completes the study of the next-to-leading order (NLO) QCD corrections to massive color-octet vector boson production at the LHC and Tevatron. The massive color-octet vector bosons are generically referred to as colorons. Building on our previous calculation of quark-initiated coloron production at NLO, we use the pinch technique to investigate coloron production via gluon fusion. We demonstrate that this one-loop production amplitude is finite, and find that its numerical...

Source: http://arxiv.org/abs/1303.1120v3

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Sep 21, 2013
09/13

by
R. Sekhar Chivukula; Stephen B. Selipsky; Elizabeth H. Simmons

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Extended technicolor theories generate potentially large corrections to the $\Zbb$ vertex which can be observed in current experiments at LEP.

Source: http://arxiv.org/abs/hep-ph/9204214v1

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Sep 20, 2013
09/13

by
Alexander Belyaev; Alexander Blum; R. Sekhar Chivukula; Elizabeth H. Simmons

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In this paper we discuss how to extract information about physics beyond the Standard Model (SM) from searches for a light SM Higgs at Tevatron Run II and CERN LHC. We demonstrate that new (pseudo)scalar states predicted in both supersymmetric and dynamical models can have enhanced visibility in standard Higgs search channels, making them potentially discoverable at Tevatron Run II and CERN LHC. We discuss the likely sizes of the enhancements in the various search channels for each model and...

Source: http://arxiv.org/abs/hep-ph/0506086v3

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Jun 28, 2018
06/18

by
R. Sekhar Chivukula; Elizabeth H. Simmons; Natascia Vignaroli

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A new heavy di-jet resonance could be discovered at the 14 TeV LHC. In this talk we present a strategy to reveal the nature of such a particle; in particular to discern whether it is a quark-antiquark (q qbar), quark-gluon (qg), or gluon-gluon (gg) resonance. The strategy is based on the study of the energy profiles of the two leading jets in the di-jet channel. Including statistical uncertainties in the signal and the QCD backgrounds, we show that one can distinguish between gg, qg, and q bar...

Topic: High Energy Physics - Phenomenology

Source: http://arxiv.org/abs/1507.06522

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Sep 23, 2013
09/13

by
R. Sekhar Chivukula; Roshan Foadi; Elizabeth H. Simmons

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In this paper we consider the effects of top quark compositeness on the electroweak parameters T-hat and S-hat and the Zbb coupling. We do so by using an effective field theory analysis to identify several promising patterns of mixing between standard model like and vector fermions, and then analyzing simple extensions of the Standard Model that realize those patterns. These models illustrate four ways in which an extended O(4) symmetry, which controls the size of radiative corrections to the...

Source: http://arxiv.org/abs/1105.5437v3

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Sep 22, 2013
09/13

by
R. Sekhar Chivukula; Shinya Matsuzaki; Elizabeth H. Simmons; Masaharu Tanabashi

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In this paper we compute the one-loop chiral logarithmic corrections to all O(p^4) counterterms in the three site Higgsless model. The calculation is performed using the background field method for both the chiral- and gauge-fields, and using Landau gauge for the quantum fluctuations of the gauge fields. The results agree with our previous calculations of the chiral-logarithmic corrections to the S and T parameters in 't Hooft-Feynman gauge. The work reported here includes a complete evaluation...

Source: http://arxiv.org/abs/hep-ph/0702218v2

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Sep 21, 2013
09/13

by
Kenneth Lane; Kevin R. Lynch; Stephen Mrenna; Elizabeth H. Simmons

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Lepton collider experiments can search for light technipions in final states made striking by the presence of an energetic photon: $e+e- \to \photon\technipion$. To date, searches have focused on either production through anomalous coupling of the technipions to electroweak gauge bosons or on production through a technivector meson (\technirho, \techniomega) resonance. This paper creates a combined framework in which both contributions are included. This will allow stronger and more accurate...

Source: http://arxiv.org/abs/hep-ph/0203065v3

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Jun 29, 2018
06/18

by
Elizabeth H. Simmons; R. Sekhar Chivukula; Pawin Ittisamai; Kirtimaan Mohan

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If an excess potentially heralding new physics is noticed in collider data, it would be useful to be able to compare the data with entire classes of models at once. This talk discusses a method that applies when the new physics corresponds to the production and decay of a single, relatively narrow, s-channel resonance. A simplifed model of the resonance allows us to convert an estimated signal cross section into model-independent bounds on the product of the branching ratios corresponding to...

Topics: High Energy Physics - Phenomenology, High Energy Physics - Experiment

Source: http://arxiv.org/abs/1611.01187